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We study the dependence on configuration in momentum space of the primordial 3-point function of density perturbations in several different scenarios: standard slow-roll inflation, curvaton and variable decay models, ghost inflation, models…

Astrophysics · Physics 2009-07-09 Daniel Babich , Paolo Creminelli , Matias Zaldarriaga

We compute the three-point cross-correlation function of the primordial curvature perturbation generated during inflation with two powers of a vector field in a model where conformal invariance is broken by a direct coupling of the vector…

Cosmology and Nongalactic Astrophysics · Physics 2013-02-08 Rajeev Kumar Jain , Martin S. Sloth

We show how to obtain the probability density function for the amplitude of the curvature perturbation, R, produced during an epoch of slow-roll, single-field inflation, working directly from n-point correlation functions of R. These…

Astrophysics · Physics 2007-05-23 David Seery , J. Carlos Hidalgo

This is a review of models of inflation and of their predictions for the primordial non-Gaussianity in the density perturbations which are thought to be at the origin of structures in the Universe. Non-Gaussianity emerges as a key…

Astrophysics · Physics 2009-11-10 N. Bartolo , E. Komatsu , S. Matarrese , A. Riotto

We revise primordial black holes (PBHs) production in the axion-curvaton model, in light of recent developments in the computation of their abundance accounting for non-gaussianities (NGs) in the curvature perturbation up to all orders. We…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-28 Giacomo Ferrante , Gabriele Franciolini , Antonio Junior Iovino , Alfredo Urbano

This is a pedagogical review on primordial non-Gaussianities from inflation models. We introduce formalisms and techniques that are used to compute such quantities. We review different mechanisms which can generate observable large…

Cosmology and Nongalactic Astrophysics · Physics 2010-09-10 Xingang Chen

In hybrid inflationary models, inflation ends by a sudden instability associated with a steep ridge in the potential. Here we argue that this feature can generate a large contribution to the curvature perturbation on observable scales. This…

Cosmology and Nongalactic Astrophysics · Physics 2010-02-21 David Mulryne , David Seery , Daniel Wesley

The formation of primordial black holes in the early universe may happen through the collapse of large curvature perturbations generated during a non-attractor phase of inflation or through a curvaton-like dynamics after inflation. The fact…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-07 Gabriele Franciolini , Andrea Ianniccari , Alex Kehagias , Davide Perrone , Antonio Riotto

Primordial black holes (PBHs) are a promising candidate for dark matter, as they can form in the very early universe without invoking new particle physics. This work explores PBH formation within a curvaton scenario featuring an…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-21 Bing-Yu Su , Nan Li , Lei Feng

Primordial Black Holes (PBH's) can form in the early Universe from the collapse of large density fluctuations. Tight observational limits on their abundance constrain the amplitude of the primordial fluctuations on very small scales which…

Cosmology and Nongalactic Astrophysics · Physics 2013-08-20 Christian T. Byrnes , Edmund J. Copeland , Anne M. Green

We compute analytic expressions for the non-linearity parameters characterizing the bi- and tri-spectrum of primordial curvature perturbations generated during an inflationary epoch of the early universe driven by an arbitrary number of…

High Energy Physics - Theory · Physics 2011-11-04 Diana Battefeld , Thorsten Battefeld

Primordial black holes as dark matter may be generated in single-field models of inflation thanks to the enhancement at small scales of the comoving curvature perturbation. This mechanism requires leaving the slow-roll phase to enter a…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-26 Matteo Biagetti , Gabriele Franciolini , Alex Kehagias , Antonio Riotto

We investigate the explicit role of negative local non-Gaussianity, $f_{\rm NL}$, in suppressing the abundance of primordial black holes (PBHs) in the single-field model of Galileon inflation. PBH formation requires significantly enhancing…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-05 Sayantan Choudhury , Kritartha Dey , Ahaskar Karde , Sudhakar Panda , M. Sami

Thanks to the rapid progress in precision cosmology in the last few years, we now have access to physical observables that may constrain the theory of inflation through the non-Gaussianity (NG) signatures in the cosmic microwave background…

Cosmology and Nongalactic Astrophysics · Physics 2013-07-19 Xinghai Zhao , Yuexing Li , Sarah Shandera , Donghui Jeong

We study the primordial density perturbations and non-Gaussianities generated from the combined effects of an inhomogeneous end of inflation and curvaton decay in hybrid inflation. This dual role is played by a single isocurvature field…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Hooshyar Assadullahi , Hassan Firouzjahi , Mohammad Hossein Namjoo , David Wands

We study non-linear primordial adiabatic and isocurvature perturbations and their non-Gaussianity. After giving a general formulation in the context of an extended delta N-formalism, we analyse in detail two illustrative examples. The first…

Astrophysics · Physics 2010-04-30 David Langlois , Filippo Vernizzi , David Wands

We study the formation of primordial black holes and the generation of gravitational waves in a class of cosmological models that are direct supersymmetric analogs of the observationally favored nonminimally coupled Higgs inflation model.…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-01 Shinsuke Kawai , Jinsu Kim

Ultra-light primordial black holes (PBHs) with masses $M_{\rm PBH}<5\times 10^8\mathrm{g}$ can dominate transiently the energy budget of the Universe and reheat the Universe through their evaporation taking place before Big Bang…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-17 Xin-Chen He , Yi-Fu Cai , Xiao-Han Ma , Theodoros Papanikolaou , Emmanuel N. Saridakis , Misao Sasaki

Loop quantum cosmology (LQC) provides a resolution of the classical big bang singularity in the deep Planck era. The evolution, prior to the usual slow-roll inflation, naturally generates excited states at the onset of the slow-roll…

Cosmology and Nongalactic Astrophysics · Physics 2018-02-07 Tao Zhu , Anzhong Wang , Klaus Kirsten , Gerald Cleaver , Qin Sheng

We investigate a new mechanism to create large curvature perturbations on small scales due to parameter resonance in a single-field inflationary model with a small periodic structure upon the potential. After reentering the horizon, the…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-17 Rong-Gen Cai , Zong-Kuan Guo , Jing Liu , Lang Liu , Xing-Yu Yang
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